Decision-makers betrayed by their wide eyes

By Ewen Callaway

WHY can’t teachers keep a secret? Because their pupils give them away. It turns out that when people make decisions, their pupils dilate, a subtle cue that could be used to predict a person’s intentions, or even converse with people with locked-in syndrome.

It is well known that pupils dilate as it gets darker, and in stressful situations as part of the “fight-or-flight” response. The reflex is mediated by the release of the hormone noradrenalin, which in animals has also been implicated in memory and decision-making. Olivia Carter, a neuroscientist at the University of Melbourne in …

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